Cross Sections for the Formation of Excited States in a Helium Target by the Impact of 0.15- to 1.0-MeV Protons and Deuterons. II. Comparison with Theory

1967 ◽  
Vol 164 (1) ◽  
pp. 151-155 ◽  
Author(s):  
E. W. Thomas
1970 ◽  
Vol 48 (2) ◽  
pp. 201-210 ◽  
Author(s):  
Y. S. Horowitz ◽  
R. E. Bell

A cooled Ge(Li) detector has been used as a total-absorption proton counter for the energy analysis of 100 MeV protons scattered from a target of natural carbon. An overall energy resolution of 0.5 MeV to 0.6 MeV (FWHM) was achieved. The differential cross sections for the excitation of the 4.43, 7.66, 9.64, 10.8, 11.8, 12.7, 14.1, 15.1, and 16.1 MeV levels have been measured at nine angles from 10 to 60° (lab). The angular distributions for the 10.8, 11.8, and 14.1 MeV levels represent the first measured proton-scattering data for these levels in the intermediate energy region (> 50 MeV). A qualitative discussion of the excited states is presented, based mainly on the shapes of the angular distributions. At large scattering angles (> 30°), the angular distribution for the 0+ level at 7.66 MeV deviates significantly from 0+ angular distributions measured in 24Mg and 28Si, suggesting different mechanisms of excitation of 0+ states in the p and s–d shells.


2016 ◽  
pp. 3564-3575 ◽  
Author(s):  
Ara Sergey Avetisyan

The efficiency of virtual cross sections method and MELS (Magneto Elastic Layered Systems) hypotheses application is shown on model problem about distribution of wave field in thin surface layers of waveguide when plane wave signal is propagating in it. The impact of surface non-smoothness on characteristics of propagation of high-frequency horizontally polarized wave signal in isotropic elastic half-space is studied. It is shown that the non-smoothness leads to strong distortion of the wave signal over the waveguide thickness and along wave signal propagation direction as well.  Numerical comparative analysis of change in amplitude and phase characteristics of obtained wave fields against roughness of weakly inhomogeneous surface of homogeneous elastic half-space surface is done by classical method and by proposed approach for different kind of non-smoothness.


2019 ◽  
Vol 34 (32) ◽  
pp. 1950259 ◽  
Author(s):  
S. M. Troshin ◽  
N. E. Tyurin

We comment briefly on relations between the elastic and inelastic cross-sections valid for the shadow and reflective modes of the elastic scattering. Those are based on the unitarity arguments. It is shown that the redistribution of the probabilities of the elastic and inelastic interactions (the form of the inelastic overlap function becomes peripheral) under the reflective scattering mode can lead to increasing ratio of [Formula: see text] at the LHC energies. In the shadow scattering mode, the mechanism of this increase is a different one, since the impact parameter dependence of the inelastic interactions probability is central in this mode. A short notice is also given on the slope parameter and the leading contributions to its energy dependence in both modes.


1957 ◽  
Vol 35 (1) ◽  
pp. 21-37 ◽  
Author(s):  
J. D. Jackson

The Monte Carlo calculations of McManus and Sharp (unpublished) for the prompt nuclear processes occurring upon bombardment of heavy elements by 400 Mev. protons are combined with a description of the subsequent neutron evaporation to determine spallation cross sections for comparison with experiment. The model employed is a schematic one which suppresses the detailed characteristics of individual nuclei, but gives the over-all behavior to be expected. Many-particle and collective effects such as alpha particle emission and fission are ignored. The computed cross sections are presented in a variety of different graphical forms which illustrate quantitatively the qualitative picture of high energy reactions first given by Serber (1947). The calculations are in general agreement with existing data when fission is not an important effect, but the agreement does not imply a very stringent test of the various features of the model.


2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Claude Duhr ◽  
Falko Dulat ◽  
Bernhard Mistlberger

Abstract We present the production cross section for a lepton-neutrino pair at the Large Hadron Collider computed at next-to-next-to-next-to-leading order (N3LO) in QCD perturbation theory. We compute the partonic coefficient functions of a virtual W± boson at this order. We then use these analytic functions to study the progression of the perturbative series in different observables. In particular, we investigate the impact of the newly obtained corrections on the inclusive production cross section of W± bosons, as well as on the ratios of the production cross sections for W+, W− and/or a virtual photon. Finally, we present N3LO predictions for the charge asymmetry at the LHC.


2000 ◽  
Vol 74 (1) ◽  
pp. 123-153 ◽  
Author(s):  
I.L. Beigman ◽  
L.A. Vainshtein ◽  
M. Brix ◽  
A. Pospieszczyk ◽  
I. Bray ◽  
...  

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